U.S. officials say the plot involved an upgrade of the underwear bomb that failed to detonate aboard a jetliner over Detroit on Christmas 2009. This new bomb was also built to be used in a passenger's underwear but contained a more refined detonation system.

The would-be suicide bomber, based in Yemen, had not yet picked a target or bought his plane tickets when the CIA stepped in and seized the bomb, officials said. It's not immediately clear what happened to the alleged bomber.

The operation unfolded even as the White House and Department of Homeland Security assured the American public that they knew of no Al Qaeda plots against the U.S. around the anniversary of bin Laden's death. The AP learned about the thwarted plot last week but agreed to White House and CIA requests not to publish it immediately because the sensitive intelligence operation was still under way. Once those concerns were allayed, the AP decided to disclose the plot Monday despite requests from the Obama administration to wait for an official announcement Tuesday[...]

U.S. officials, who were briefed on the operation, insisted on anonymity to discuss the case.

It's not clear who built the bomb, but, because of its sophistication and its similarity to the Christmas bomb, authorities suspected it was the work of master bomb maker Ibrahim Hassan al-Asiri. Al-Asiri constructed the first underwear bomb and two others that Al Qaeda built into printer cartridges and shipped to the U.S. on cargo planes in 2010.

Apparently, there are many disconnects on who exactly was briefed on this terror plot.

As a result of close cooperation with our security and intelligence partners overseas, an improvised explosive device (IED) designed to carry out a terrorist attack has been seized abroad. The FBI currently has possession of the IED and is conducting technical and forensics analysis on it. Initial exploitation indicates that the device is very similar to IEDs that have been used previously by al Qaeda in the Arabian Peninsula (AQAP) in attempted terrorist attacks, including against aircraft and for targeted assassinations. The device never presented a threat to public safety, and the U.S. government is working closely with international partners to address associated concerns with the device. We refer you to the Department of Homeland Security, including the Transportation Security Administration, regarding ongoing security measures to safeguard the American people and the traveling public.

BTW I failed to mention the awesome job our counter terror community did on thwarting this attack. Thank you!